The application's long-term objective is to improve the treatment of acute ischemic stroke by using mechanical embolectomy for arterial recanalization. The specific aim of this project is to design and test various versions of the Clot Retriever Device (CRD), a helix shaped nitinol device made to ensnare and retrieve thrombo-emboli from cerebral arteries. CRDs will be designed for embolectomy in 1.5mm to 5mm diameter arteries. After mechanical characterization including tensile strength, the CRD prototypes will be tested in a silicon model of human brain arteries and in a flow-model of thrombo-embolization. The optimal prototypes will be used to perform thrombo-embolectomy in the carotid artery branches of 6 swine. Despite FDA approval of IV t-PA for treatment of ischemic stroke 4 years ago, less than 2 percent of U.S stroke patients per year benefit from this treatment. The main reason is the narrow, 3-hour time-window for treatment, after which the risk of hemorrhage due to thrombolysis outweighs the benefit of recanalization. Because mechanical embolectomy does not use a thrombolytic agent, the time window for recanalization could be significantly expanded without increased risk of hemorrhage. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE